Version: 71.0.3577.0 (Official Build)Revision fc334a55a70eec12fc77853c53979f81e8496c21-refs/branch-heads/3577@{#1}(32/64-bit)
OS: Mac OS X(10.13.1,10.14.1,10.13.6)

What steps will reproduce the problem?
1. Freshly launch chrome,navigate to NTP and right click to open context menu
2. Now select cast option from context menu to open 'Cast' overlay and press 'Tab' key , observe
 
Actual: Focus is not seen on 'Learn More' link on pressing 'Tab' key
Expected: Focus should be seen on 'Learn More' link on pressing 'Tab' key

This is regression issue, broken in ‘M 67’ and below is the bisect info :
Good build: 67.0.3378.0 (Revision: 544932)
Bad build:  67.0.3379.0 (Revision: 545318)
 
You are probably looking for a change made after 545257 (known good), but no later than 545258 (first known bad).

CHANGELOG URL:
The script might not always return single CL as suspect as some perf builds might get missing due to failure.
  
https://chromium.googlesource.com/chromium/src/+log/0ace60f0bda35d4788e12314314758465ccf70f5..e09df9251bdc1f717aa76df1629a04143971a15e

Suspect : https://chromium.googlesource.com/chromium/src/+/e09df9251bdc1f717aa76df1629a04143971a15e

From the CL above, assigning the issue to the concern owner 

@ellyjones - Could you please check whether this is caused with respect to your change, if not please help us in assigning it to the right owner.

Note : 
1. This issue is also reproducible on M-69 stable (build # 69.0.3497.100), M-70 Beta (build # 70.0.3538.54) and M-71 Dev (build # 71.0.3573.0)
2. This issue is not seen on Windows (7,8,8.1,10) and Linux (14.04 LTS)

Thanks!
 

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